Usage of clamp ammeter
Firstly, correctly select the voltage level of the clamp ammeter, and check whether its external insulation is good, whether it is damaged, whether the pointer swings flexibly, and whether the jaw is corroded. According to the motor power, the rated current is estimated to select the measuring range of the meter.
Clamp-type meter jaws should be closed tightly when measuring. If there is noise after closing, open the jaws and re-install them once. If the noise still cannot be eliminated, check whether the joint surfaces on the magnetic circuit are smooth and clean, and wipe them clean when there is dust.
The clamp meter can only measure the current of one phase conductor at a time, and the conductor to be measured should be placed in the center of the clamp window. It is not allowed to clamp all the multiphase conductors into the window for measurement.
The voltage of the tested circuit should not exceed the value indicated on the clamp meter, otherwise it will easily lead to grounding accident or electric shock danger.
Read the instructions carefully before using the clamp ammeter to find out whether it is an AC or AC/DC clamp ammeter.
Because of the low accuracy of the clamp ammeter itself, the following methods can be adopted when measuring small current: first, wind the conductor of the circuit to be measured several times, and then put it into the jaw of the clamp ammeter for measurement. At this time, the current value indicated by the clamp meter is not the actual value to be measured, and the actual current should be the reading of the clamp meter divided by the number of windings of the wire.
Measure that working current of the cage asynchronous motor in operation. According to the current, whether the motor works normally can be checked to ensure the safe operation of the motor and prolong its service life.
When measuring, you can measure every phase or three phases. At this time, the number on the meter should be zero (because the phasor sum of three-phase currents is zero). When there are two phase wires in the jaw, the value displayed on the meter is the current value of the third phase. By measuring each phase current, you can judge whether the motor is overloaded (the measured current exceeds the rated current value), and whether there is a problem with the power supply voltage inside the motor or (other forms of devices that can be converted into electric energy are called power supplies).
